Hintze Centre for Astrophysical Surveys

Abstract:

We construct mass models of 28 S0-Sb galaxies. The models have an axisymmetric stellar component and a NFW dark halo and are constrained by observed KS-band photometry and stellar kinematics. The median dark halo virial mass is 1012.8 M⊙, and the median dark/total mass fraction is 20% within a sphere of radius r1/2, the intrinsic half-light radius, and 50% within R25. We compare the Tully-Fisher relations of the spirals and S0s in the sample and find that S0s are 0.5 mag fainter than spirals at KS-band and 0.2 dex less massive for a given rotational velocity. We use this result to rule out scenarios in which spirals are transformed into S0s by processes which truncate star formation without affecting galaxy dynamics or structure, and raise the possibility of a break in homology between spirals and S0s. © 2010 American Institute of Physics.

Abstract:

We show that high quality laser guide star (LGS) adaptive optics (AO) observations of nearby early-type galaxies are possible when the tip-tilt correction is done by guiding on nuclei while the focus compensation due to the changing distance to the sodium layer is made 'open loop'. We achieve corrections such that 40% of flux comes from R<0.2 arcsec. To measure a black hole mass (M•) one needs integral field observations of both high spatial resolution and large field of view. With these data it is possible to determine the lower limit to M• even if the spatial resolution of the observations are up to a few times larger than the sphere of influence of the black hole. © 2010 American Institute of Physics.

Abstract:

We investigate the accuracy of mass determinations MBH of supermassive black holes in galaxies using dynamical models of the stellar kinematics. We compare 10 of our MBH measurements, using integral-field OASIS kinematics, to published values. For a sample of 25 galaxies we confront our new MBH derived using two modeling methods on the same OASIS data. © 2010 American Institute of Physics.